Premature babies, like the rest of us, need vitamin D in order to develop strong bones.

A new, small study at the University of Nebraska Medical Center means preemies now will get twice the previously recommended dose of vitamin D — something some other hospitals around the area say they’re doing, too.

Recommendations for just how much vitamin D premature babies should be given, and how much they should have in their blood, have varied considerably among major medical groups in the United States and abroad.

In a study involving some of the earliest preemies, the researchers found that doubling the standard dose of vitamin D from 400 international units a day to 800 IU not only proved safe but also raised babies’ blood levels to a more optimal number and improved their bone density by the time they reached their actual due date and were ready to go home. The study was published this month in PLOS One, a leading peer-reviewed journal. (“PLOS” stands for “Public Library of Science.”)

Dr. Ann Anderson Berry, associate professor in UNMC’s division of newborn medicine, said the neonatal intensive care unit at the Nebraska Medical Center will change its practice to supplementing with 800 IU a day now that the data has been published.

Anderson Berry, the paper’s first author, is the NICU’s medical director. She’s been hearing from other units indicating that they will do the same.

Ideally this would catch on more widely in other NICUs, said Anderson Berry, who has conducted previous research on vitamin D in preterm babies.

While the numbers weren’t statistically significant, the researchers also noted a trend toward greater growth in length among the babies who received the higher dose of the vitamin. That’s one question they’d want to follow up in a larger trial.

“We’re making the bones denser, but are we also getting appropriate growth (in length), getting babies to reach their genetic potential despite their prematurity?” she said.

The study involved 32 infants born between four months and two months early. Half got 400 IU of vitamin D while in the hospital and the other half received 800 IU. After four weeks, the 400 IU group had a median level of 80 nanomoles per liter of the nutrient in their blood, although some still were lower. The 800 IU group got to a median of 105 nanomoles per liter and had no side effects. Recommended targets are between 50 nanomoles per liter to support bone health and 80 nanomoles per liter to support immune health and respiratory development.

The babies in the higher-dose group also had higher bone density, a measure of bone health, in scans than those in the lower-dose group, Anderson Berry said. Babies who start with lower bone density are starting behind other babies when it comes to bone growth.

All babies will continue to be sent home on 400 IU of vitamin D, based on the current recommendations for all full-term babies, whether breast-fed or formula-fed.

Locally, other NICUs already are well aware of the importance of the vitamin.

Dr. David Minderman, medical director of the NICU at Methodist Women’s Hospital, said he and his staff have been giving the unit’s smallest babies 800 IU of vitamin D for two or three years, based on their reading and discussions with Anderson Berry, a longtime colleague.

All other babies in the NICU get 400 IU, according to the American Academy of Pediatrics’ recommendation.

Dr. Nicole Birge, medical director of the NICU at Children’s Hospital & Medical Center, said the hospital’s group of neonatologists, which includes Anderson Berry, planned to discuss the findings at a group meeting Wednesday.

“Now that this is out there, it would be nice to mirror ourselves” to the medical center’s practice, she said. Currently, the Children’s NICU screens the vitamin D levels of all the babies it treats, which includes those born preterm and full-term babies with other health issues, and brings them to a certain level if they’re deficient. They repeat the screening every six weeks and adjust dosing based on blood levels.

CHI Health’s NICUs at Creighton University Medical Center-Bergan Mercy and Lakeside have supplemented up to 800 IU when babies’ calcium or vitamin D levels are low, said Carla Christensen, assistant professor of pharmacy with the Creighton School of Pharmacy and Health Professions. Otherwise, they’ve been supplementing with 400 IU in addition to what’s in breast milk or formula since about 2010.

In addition to promoting bone health, vitamin D also is known to help prevent infection and inflammation and is believed to play a role in lung disease, which is a big problem in premature babies.

The UNMC study, which was designed to make sure the higher dose would be safe in the most at-risk babies the NICU treats, didn’t include enough infants to determine whether supplementing with the vitamin would produce those outcomes. But Anderson Berry said she believes future studies will address those targets.

As for administering the vitamin, she said, other NICU staff with whom she has corresponded have been relieved to know that the researchers have been able to give babies just two drops of concentrated vitamin D. A dose of the regular version would be difficult to administer to the tiniest babies — some of those she treated weighed about a pound — who can take milk a milliliter at a time.

Anderson Berry said the best news was that the study demonstrated that they could safely give the babies the larger dose and that they responded to it. The study is one of the first to look at higher dosing of vitamin D in premature infants, she said.

The study’s senior author is Corrine Hanson, an associate professor in the UNMC College of Allied Health Professions’ medical nutrition education division. Elizabeth Lyden, a biostatistician in UNMC’s College of Public Health, is a contributing author.